Poorly 35i (Now Fixed)(sort of)

[robbee]

Thanks Maniac,

Yes, a 2009 35i dct, with only 15,800 miles, so seems like the failure of the injectors are the destiny of all 35i's regardless of mileage. Also just had the big 4 yearly service a month ago, though Specialist Cars Stevenage didn't pick anything up.

Next is to find a London dealer to trust to undertake the repair as Stevenage is 60 miles away. I still have the insured warranty (nearly didn't renew this year) but not emergency cover so they will only recover to the nearest dealer. Have a choice of Barons Kentish town, the closest (previously Spires with poor reputation), Stephen James Enfield or Sytner Chigwell, assuming the car will make it there, though the manual says I could damage the catalytic converter if driving while the yellow engine light flashes, which will then not be covered by the warranty (reading the small print). Do you think driving lightly could cause damage to the Cat?

Sorry to hear yours is still not 100% - if its poor on power, could mean un-burnt fuel also getting to the catalytic converter, causing damage to that. Wonder what BMW warranty would say then - Did they advise you not to drive until fully resolved?. Did you have the yellow engine warning light flash up on yours at an time? Why would a software update make a difference, other than updated/different model injectors?

I'm annoyed for you that your garage released the car with the low power, and didn't already double check the injector registration and know to update the software. Did you also check the decouplers were installed as suggested by R.E92? Seems ridiculous we have to ask the garage if they did/are going to do, all of this - I would be too embarrassed. Hence my dilemma of which dealer to choose to undertake this work.

Hope yours gets sorted soon.

robbee

 

[Maniac]

CAR IS back from a two day stint at the dealership.

They identified a cracked valve cover and perished PCV pipe.

Cover is replaced and pipe on back order.

Startup tomorrow will tell me if the cover replacement has helped.

Invoice value around a grand. So thankful for paid warranty. But another £250 excess out after October’s £250 for the water pump and injectors.

Guys, I can’t recommend the N54 any longer. Terrific when working but is not ageing well.

Next outlay if something else doesn’t break is walnut blasting and a new NS adaptive shock they’ve found leaking.

This car has been pampered. God Knows what less pampered cars are going to be like as they age.

 

[ph001]

Yeh, pretty scary things when out of warranty but you would hope if you can get shocks, HPFP and injectors all done in warranty the new ones would be better engineered / more reliable. That's certainly the case for the injectors afaik.

 

[dario]

CAR IS back from a two day stint at the dealership.

They identified a cracked valve cover and perished PCV pipe.

Cover is replaced and pipe on back order.

Startup tomorrow will tell me if the cover replacement has helped.

Invoice value around a grand. So thankful for paid warranty. But another £250 excess out after October’s £250 for the water pump and injectors.

Guys, I can’t recommend the N54 any longer. Terrific when working but is not ageing well.

Next outlay if something else doesn’t break is walnut blasting and a new NS adaptive shock they’ve found leaking.

This car has been pampered. God Knows what less pampered cars are going to be like as they age.

so when did they crack the vale cover..........?

 

[Maniac]

They don’t accept it’s their doing. Looking online this seems to be another N54 weakness. It just happens due to a design fault. Likely missed or unseen by many that have it

https://www.pistonheads.com/gassing/topic.asp?h=0&f=72&t=1711110&i=999999

It’s not resolved the poor cold running. Waiting on the PCV pipe as the next test now.

 

[dario]

They don’t accept it’s their doing. Looking online this seems to be another N54 weakness. It just happens due to a design fault. Likely missed or unseen by many that have it

https://www.pistonheads.com/gassing/topic.asp?h=0&f=72&t=1711110&i=999999

It’s not resolved the poor cold running. Waiting on the PCV pipe as the next test now.

you'll find out soon enough! it will either run better or not. probably the pipe all along!

 

[Maniac]

So it went in yesterday for the replacement pipe (crankcase vent/emissions control).

It ran fine on the way there just like old times which was v odd.

They’ve replaced the pipe and I’ve just taken it from a stone cold start run. It was normal just like yesterday.

So at this point I don’t know whether the pipe has sorted it or it’s just a fluke.

 

[dario]

So it went in yesterday for the replacement pipe (crankcase vent/emissions control).

It ran fine on the way there just like old times which was v odd.

They’ve replaced the pipe and I’ve just taken it from a stone cold start run. It was normal just like yesterday.

So at this point I don’t know whether the pipe has sorted it or it’s just a fluke.

Bugger

 

[Maniac]

Third day and 2nd cold start ran as normal so it’s looking good. No drop off power or particularly weird gear changes. Fingers crossed.

 

[Maniac]

So it’s been stood unused for a few days and today’s first cold start saw some slight hesitation before gear changes which quickly reduced as the car warmed up. There’s no loss of power during or after changes as there was before. In fact it’s more responsive than it’s been in years.

So now it’s left me wondering if it was always a bit sluggish/you could feel the gear changes when it was cold and I’m focusing on something that’s as it should be.

 

[dario]

So it’s been stood unused for a few days and today’s first cold start saw some slight hesitation before gear changes which quickly reduced as the car warmed up. There’s no loss of power during or after changes as there was before. In fact it’s more responsive than it’s been in years.

So now it’s left me wondering if it was always a bit sluggish/you could feel the gear changes when it was cold and I’m focusing on something that’s as it should be.

looking a gift horse in the mouth?

 

[Maniac]

Possibly. Sensitivity on the throttle is hugely improved, I can’t remember it being so instant. I suspect the pipe or valve cover has been an issue for a long time, finished off or shown up by the injector replacement works.

Dario, do me a favour tho would you. When you use the Z next, see if you can feel the gear changes when setting off with a stone cold car. If you can and they smooth out to imperceptible when warmed up, then what I’m seeing there is normal.

I always felt I could never feel the changes whether warm or cold but perhaps I’m just mistaken.

The sensation I’m getting from cold start is as if it lifts off the throttle just a bit before the shift up.

 

[dario]

Possibly. Sensitivity on the throttle is hugely improved, I can’t remember it being so instant. I suspect the pipe or valve cover has been an issue for a long time, finished off or shown up by the injector replacement works.

Dario, do me a favour tho would you. When you use the Z next, see if you can feel the gear changes when setting off with a stone cold car. If you can and they smooth out to imperceptible when warmed up, then what I’m seeing there is normal.

I always felt I could never feel the changes whether warm or cold but perhaps I’m just mistaken.

The sensation I’m getting from cold start is as if it lifts off the throttle just a bit before the shift up.

I was out in it this morning in cold conditions and the clutch/gear thing is pretty much as described. worst bit when cold is coming in to a junction or a roundabout, sometimes it likes to select too low a gear like first when second would have been the better bet. clutch changes can be felt when cold, but warm is another thing entirely, like seamless gearbox.

thats the problem with stuff like this, paranoia is a difficult thing to disengage from when trying to be objective lol

 

[Maniac]

Good to know. Then I guess we’re all good and it was the vacuum leak that caused the power loss issues.

 

[dario]

Sigh, the rough when cold running has returned. The longer the car stands the rougher it's next start. Still no codes though, don't want to risk diagnostic fees until it's showing codes.

It's not a regular misfire, it's spotty. It's also bouncing revs when I try and hold them other than at idle.

but surely, they still haven't fixed the original problem have they?

 

[Maniac]

Yes. Original issue was misfire. That was resolved by new injectors.

When returned I had no misfire but a weird power loss around shifts, it felt like it would stall when slowing / shifting down and felt like someone hit the brakes when shifting up.

That’s been resolved by the new valve cover and PCV pipe.

 

[Maniac]

SO whatever caused the improvement was short lived. We’re back to the power loss before shifting up again on cold starts.

This is really starting to annoy me now.

 

[Smartbear]

SO whatever caused the improvement was short lived. We’re back to the power loss before shifting up again on cold starts.

This is really starting to annoy me now.

You could have a smoke test to check for any further potential air leaks if it hasn’t been done already.
The symptoms you describe are very similar to the ones displayed by Ann’s mini, that was a faulty vanos solenoid causing hesitation on gearchanges & an imprecise “fluffy” feel on reapplication of throttle or pulling away from standstill, that never triggered an eml either.
Rob

 

[Maniac]

THats the thing, it could be lots of things and thedealer doesn’t seem to Be able to sense it mainly as it has to be stood overnight and the issue lasts just the first few minutes of driving.

Took it out for a proper WOT traction fest of some damp back roads today and it didn’t miss a beat. I half hoped something would cause an EML but I’m not that lucky.

 

[Maniac]

So I’m still not happy with how it’s running. Back to the dealers for 3 days and they don’t see anything wrong but then they have no reference point as to how it should be. They reset the DCT in case that was the issue which has resulted in a very sharp initial bite on set off or hills.

Two things I have discovered, a recent cold start at ambient 13C was much better than one this morning at 1C. Also 99 Ron fuel improves the situation over 95 Ron.

To me this goes right back to the injectors again, either faulty or wrongly configured.

I’m waiting on a response from the mechanic that worked on it most recently and then I’m going to insist they double check the injectors and coding configuration.